sprung Out - measuring Spring Sag - Photo 08

Old leaf springs can sag over time and lose tension, and then you’re left with a truck that rides too low or uneven. To check for proper spring arch, Hardy runs a straight edge between the center of the spring’s bushings and measures to the bottom of the center bolt hole. For the ’78 Bronco the stock spring should be between 7 1/4 to 8 inches, and we were well within tolerance. A quick Google search should help you find the stock arch-height for your specific vehicle.